The present invention relates to a device for counting doses issued by a substance dispenser, and more particularly by an inhaler of the kind used, for example, in the field of pharmacy.
In medical applications in particular, it is often necessary to spray some particular number of doses of substance contained in the dispenser, e.g. on a daily basis. To prevent mistakes in handling and/or dosage, it is desirable to provide means that serve to display the number of doses that have been sprayed, or that remain to be sprayed if the initial display gives the maximum number of doses that can be displayed (up-counter or down-counter).
Proposals have already been made, in patent EP-0 269 496 for a counter that counts actuation of the pushbutton and that comprises a count wheel mounted to rotate coaxially with the pushbutton and provided with a crown of axially extending peripheral teeth. A flexible blade secured to the pushbutton drives the wheel causing it to rotate when the pushbutton is actuated. That device is simple and cheap, but because it has only one wheel it is limited as to number of doses that can be counted.
Also, since that device transforms the axial motion of the pushbutton into rotary motion of the wheel, it is unsuitable for operating independently of the actuating pushbutton.
An object of the present invention is to provide a device for counting doses that is capable of counting an arbitrary number of doses (typically several tens to several hundreds of doses) and capable of being actuated by a member exerting movement in translation.